Push type switch

ABSTRACT

A push type switch which enables an operator to obtain an upscale impression when he operates the push type switch. A switch body  3  is rigidly fixed to a printed wiring board  5 . A casing  7  having a plurality of guide grooves  71   h  is fixed to the printed wiring board  5 . A plurality of rails  91   a  provided on a knob  9  capable of transmitting a pushing force to the switch body  3  are slidably inserted into the guide grooves  71   h  such that the knob  9  can slide on the casing  7 . A grease is applied to the guide grooves  71   h  and the rails  91   a . The viscosity of the grease is set to be within a range of 1000 to 2750 Pa.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a push type switch, and moreparticularly to a push type switch which is capable of creating anupscale impression when operating (pushing) the push type switch.

2. Description of the Related Art

Conventionally, a key switch is known which is comprised of a membranesubstrate, a pair of fixed contact points, a click rubber, a frame, anda key top (see e.g. Japanese Laid-Open Patent Publication (Kokai) No.2004-71306 (Paragraph numbers [0011] to [0014], FIG. 1))

The membrane substrate is disposed on a chassis e.g. of electronicequipment.

The pair of fixed contact points are provided on the membrane substrate.

The click rubber has a generally domed shape, and covers the pair offixed contact points. The click rubber has a conductive rubber providedon an inner surface thereof. The conductive rubber is opposed to thepair of fixed contact points in a manner spaced therefrom.

The frame is opposed to the membrane substrate and the click rubber in amanner slightly spaced therefrom. The frame includes a slide guide thathas a hollow cylindrical shape.

The key top has a sliding portion. The sliding portion is in the form ofan octagonal column and inserted into the slide guide, such that itslides in the direction of the thickness of the chassis.

The slide guide and the sliding portion are coated with a grease forsmooth sliding and reduction of generation of noise.

When the key top is pushed with a finger, the sliding portion is causedto slide to press the click rubber. When the click rubber is pressed toa certain extent, it is inverted in shape, i.e. changed from a convexstate into a concave state, whereby the conductive rubber is broughtinto contact with the pair of fixed contact points. As a result, thepair of fixed contact points are closed. Further, when the click rubberis inverted in shape, a click feeling is created.

When the finger is released from the key top, the key top returns to itsoriginal position by the resilience thereof, and the conductive rubbermoves away from the pair of fixed contact points.

An upscale impression is demanded of a push type switch disposed on aninstrumental panel for an automotive vehicle.

To impart the upscale impression to the above key switch, it isenvisaged to use an expensive material for the key top, or decorates thekey top with a special color or pattern.

However, there was a limit to creating the upscale impression, unless anoperation feeling in operating the key switch is enhanced.

SUMMARY OF THE INVENTION

The present invention has been made in view of these circumstances, andan object thereof is to provide a push type switch which is capable ofcausing an operator to sense an upscale impression when he operates thepush type switch.

To attain the above object, the present invention provides a push typeswitch comprising a switch body, a fixing member to which the switchbody is rigidly fixed, a movable member slidably supported by the fixingmember such that the movable member can transmit a pushing force to theswitch body, and a grease applied to sliding portions of the fixingmember and the movable member, wherein a viscosity of the grease iswithin a range of 1000 to 2750 Pa.

According to this push type switch, the viscosity of the grease iswithin a range of 1000 to 2750 Pa, so that when an operator pushes themovable member with his finger, he feels that an appropriate weight (aforce his fingertip receives from the grease) is transmitted to hisfingertip, and recognizes that the movable member is moved more slowlythan in the prior art. Further, the operator can feel that rattling ofthe movable member and generation of noise are more suppressed than inthe prior art. As a result, the push type switch according to thepresent invention is capable of giving an upscale impression to theoperator when he operates the push type switch.

Preferably, the grease is a fluorine-based grease.

According to this preferred embodiment, since the grease is afluorine-based grease, no significant changes in the viscosity arecaused by temperature. As a result, it is possible to prevent theoperation feeling from being changed due to changes in temperature.

Preferably, a guide groove is formed in one of the fixing member and themovable member, and a rail for sliding relative to the guide groove isformed on the other of the fixing member and the movable member.

According to this preferred embodiment, a guide groove is formed in oneof the fixing member and the movable member, and a rail for slidingrelative to the guide groove is formed on the other of the fixing memberand the movable member. Therefore, the movable member can slide morestably. Further, according to the present invention, it is possible tofurther enhance the upscale impression during operation of the push typeswitch.

More preferably, a first grease reservoir is formed in at least one ofthe guide groove and the rail.

According to this preferred embodiment, since a first grease reservoiris formed in at least one of the guide groove and the rail, loss of thegrease is caused only in a small amount even after the push type switchis used for a long time period. This makes it possible to maintain anexcellent operation feeling for a long time period.

More preferably, a second grease reservoir is formed in one end ofeither the guide groove or the rail.

According to this preferred embodiment, since a second grease reservoiris formed in one end of either the guide groove or the rail, loss of thegrease is caused only in a small amount even after the push type switchis used for a long time period. This makes it possible to maintain anexcellent operation feeling for a long time period.

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a push type switch accordingto a first embodiment of the present invention;

FIG. 2 is a perspective view of a knob of the FIG. 1 push type switch,as viewed obliquely from below.

FIG. 3A is a front view of the FIG. 1 push type switch;

FIG. 3B is a plan view of the FIG. 1 push type switch;

FIG. 3C is a bottom view of the FIG. 1 push type switch;

FIG. 3D is a right side view of the FIG. 1 push type switch;

FIG. 4 is a cross-sectional view taken on line IV-IV of FIG. 3A;

FIG. 5 is a cross-sectional view taken on line V-V of FIG. 3D;

FIG. 6 is an enlarged view of part A appearing in FIG. 5;

FIG. 7 is a cross-sectional view taken on the same line as in FIG. 4, ina state where the knob is not pushed;

FIG. 8 is a cross-sectional view taken on the same line as in FIG. 4, ina state where the knob is pushed;

FIG. 9 is a graph showing the relationship between the average ranks ofsamples and the viscosities of greases;

FIG. 10 is a view showing a table of evaluation items and evaluationscores of the samples on a seven-point scale;

FIG. 11 is a graph showing the relationship between the averageevaluation scores of the respective samples as to the feeling ofsoftness obtained during operation of the knob and the viscosities ofthe greases;

FIG. 12 is a graph showing the relationship between the averageevaluation scores of the respective samples as to rattling of the knoband the viscosities of the greases;

FIG. 13 is a graph showing the relationship between the averageevaluation scores of the respective samples as to generation of noiseduring the operation of the knob and the viscosities of the greases;

FIG. 14 is a graph showing the relationship between the sliding speedand the sliding resistance of the knob exhibited when a low-viscositygrease is used or when a high-viscosity grease is used;

FIG. 15 is a graph in which the horizontal axis represents the stroke ofthe knob, and the vertical axis represents the speed of the knob and theload on the knob;

FIG. 16 is a cross-sectional view showing a sliding portion of a firstvariation of the first embodiment;

FIG. 17 is a cross-sectional view showing a sliding portion of a secondvariation of the first embodiment;

FIG. 18 is an enlarged cross-sectional view of part A of a thirdvariation of the first embodiment;

FIG. 19 is an enlarged cross-sectional view of part A of a fourthvariation of the first embodiment;

FIG. 20 is an enlarged cross-sectional view of part A of a fifthvariation of the first embodiment;

FIG. 21 is an enlarged cross-sectional view of part A of a sixthvariation of the first embodiment;

FIG. 22 is a cross-sectional view of a sliding portion of a seventhvariation of the first embodiment;

FIG. 23 is an exploded perspective view of a push type switch accordingto a second embodiment of the present invention;

FIG. 24 is a perspective view of the FIG. 23 push type switch, in astate having part of a casing thereof cut off, and presented in aninverted position;

FIG. 25 is an enlarged view of part B appearing in FIG. 24; and

FIG. 26 is a cross-sectional view of the FIG. 23 push type switch.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the drawings.

FIG. 1 is an exploded perspective view of a push type switch accordingto a first embodiment of the present invention; FIG. 2 is a perspectiveview of a knob of the FIG. 1 push type switch, as viewed obliquely frombelow; FIG. 3A is a front view of the FIG. 1 push type switch; FIG. 3Bis a plan view of the FIG. 1 push type switch; FIG. 3C is a bottom viewof the FIG. 1 push type switch; FIG. 3D is a right side view of the FIG.1 push type switch; FIG. 4 is a cross-sectional view taken on line IV-IVof FIG. 3A; FIG. 5 is a cross-sectional view taken on line V-V of FIG.3D; and FIG. 6 is an enlarged view of part A appearing in FIG. 5.

As shown in FIGS. 1 to 6, the push type switch is comprised of a switchbody 3, a printed wiring board 5, a casing 7, and a knob (movablemember) 9.

The switch body 3 is disposed at a corner of the printed wiring board 5.The switch body 3 includes a click board 31, a pair of fixed contactpoints (not shown), and a movable contact point (not shown). The clickboard 31 is made of an elastic material having insulating propertiessuch that it has a generally domed shape. The click board 31 has aprotrusion 31 a formed on the top thereof. The pair of fixed contactpoints are arranged on the printed wiring board 5, and covered by theclick board 31. The movable contact point is disposed on an innersurface of the click board 31 in a manner opposed to the pair of fixedcontact points.

The printed wiring board 5 is formed with a conductor pattern (notshown). Part of the conductor pattern is connected to the pair of fixedcontact points.

The casing 7 is formed of resin as a unitary member, and includes ahollow section 71, a frame 72, and an accommodating section 73.

The hollow section 71 has a generally hollow prismatic shape, andincludes three pillar-like portions 71 a, and a plurality of plate-likeportions 71 d formed between the three pillar-like portions 71 a. Thepillar-like portions 71 a extend along the direction of the height H1(see FIG. 1) of the hollow section 71. The pillar-like portions 71 a arelarger in height than the plate-like portions 71 d, and hence the upperends of the pillar-like portions 71 a protrude from the upper end facesof the plate-like portions 71 d, and the protruding portions serve asgrease supply protrusions 71 e (see FIGS. 1 and 4). The pillar-likeportions 71 a each have an outer side surface formed with a guide groove71 h that extends along the direction of the height H1 of the hollowsection 71. The grease supply protrusions 71 e are formed with greasesupply reservoirs (second grease reservoirs) 71 k. The grease supplyreservoirs 71 k communicate with the guide grooves 71 h, respectively,and extend in a manner widened toward the ends thereof.

The two plate-like portions 71 d opposed to each other are formed withprotrusions 71 p, respectively. The protrusions 71 p are generallywedge-shaped.

The frame 72 surrounds one end of the hollow section 71, and includesthree grease supply reservoirs (second grease reservoirs) 72 a. Thegrease supply reservoirs 72 a communicate with the guide grooves 71 h.

The accommodating section 73 is formed at a corner of the frame 72 in amanner such that a half thereof extends into the hollow section 71 (seeFIG. 5). The top of the accommodating section 73 is formed with a hole73 a. The accommodating section 73 accommodates the switch body 3.

The above described printed wiring board 5 and the casing 7 constitute afixing member having the switch body 3 fixed thereto.

The knob 9 is approximately box-shaped and formed of resin. The knob 9has a skirt 91, a pushed portion 92, and a pushing portion 93.

The skirt 91 has a generally hollow prismatic shape, and includes threerails 91 a, and a plurality of plate-like portions 91 d formed betweenthe three rails 91 a. The rails 91 a extend along the direction of theheight H2 (see FIG. 1) of the knob 9. The rails 91 a are larger inheight than the plate-like portions 91 d, so that the foremost ends ofthe rails 91 a protrude from the end faces of the plate-like portions 91d, and the protruding portions serve as grease supply protrusions 91 e(see FIG. 1). The rails 91 a are formed with respective grease-holdinggrooves (first grease reservoirs) 91 h. The grease-holding grooves 91 hextend along the direction of the length of the rails 91 a.

The rails 91 a are slidably inserted into the associated guide grooves71 h. As described above, in the first embodiment, the guide groove 71 hand the rails 91 a constitute respective sliding portions.

The grease supply protrusions 91 e enter the grease supply reservoirs 72a, when the knob 9 is closest to the frame 72.

Opposed two of the plate-like portions 91 d are formed with holes 91 p,respectively. The holes 91 p are rectangular in shape and have theassociated protrusions 71 p received therein. In this state, theprotrusions 91 p can be relatively moved within a predetermined range.This range determines the stroke of the knob 9, which is thus preventedfrom falling off the casing 7.

The pushed portion 92 is for being pushed with a finger. The pushedportion 92 has a plate-like shape, and is connected to one end of theskirt 91. The pushed portion 92 has three grease supply reservoirs(second grease reservoirs) 92 a. The three grease supply reservoirs 92 aare formed in a manner surrounding the rails 91 a, and communicate withthe grease-holding grooves 91 h. The grease supply reservoirs 92 areceive the grease supply protrusions 71 e, when the knob 9 is closestto the frame 72.

The pushing portion 93 is disposed at a corner of the pushed portion 92,and connected to the skirt 91. The foremost end of the pushing portion93 is inserted into the accommodating section 73 via the hole 73 a. Thepushing portion 93 pushes the protrusion 31 a of the click board 31.

Grease 11 is applied to the guide grooves 71 h and the rails 91 a (seeFIG. 6). As the grease 11, there is used a fluorine-based grease theviscosity of which is within a range of 1000 to 2750 Pa.

It should be noted that the viscosity of the grease 11 is expressed interms of torque. The torque is defined here as a shearing force (inunits of Pa) obtained when 0.2 cc of the grease is placed on a plate ofa rotation viscometer, and the plate is rotated at a rotational speed of10 rpm.

FIG. 7 is a cross-sectional view taken on the same line as in FIG. 4, ina state where the knob is not pushed, and FIG. 8 is a cross-sectionalview taken on the same line as in FIG. 4, in a state where the knob ispushed.

Next, a description will be given of the operation of the push typeswitch according to the present embodiment.

In a state where the operator is not pushing the knob 9 with his finger(the state shown in FIG. 7), the knob 9 is urged by the resilience ofthe click board 31 via the protrusion 31 a, whereby the knob 9 is at aposition away from the printed wiring board 5.

When the operator pushes the knob 9 with his finger against theresilience of the click board 31, the pushing force is transmitted tothe click board 31 via the pushing portion 93 and the protrusion 31 a,whereby the click board 31 is progressively crushed. When the pushingforce applied to the click board 31 exceeds a predetermined value, theclick board 31 is inverted in shape, i.e. changed from a convex stateinto a concave state, as shown in FIG. 8. At this time, a click feelingis obtained, and the movable contact point is brought into contact withthe pair of fixed contact points, whereby the switch body 3 is turnedon.

When the operator releases his finger from the knob 9, the knob 9 isreturned to its original position by the resilience of the click board31, and the movable contact point is moved away from the pair of fixedcontact points, whereby the switch body 3 is turned off.

Next, a description will be given of the circulation of the grease 11.

In the state where the operator is not pushing the knob 9 with hisfinger, the knob 9 is spaced away from the printed wiring board 5 by theclick board 31, as described above. In this state, the grease supplyprotrusions 71 e and 91 e are away from the grease supply reservoirs 92a and 72 a, respectively.

When the knob 9 is pushed to be moved toward the printed wiring board 5,the grease 11 hardly leaks from the guide grooves 71 h since the grease11 within the guide grooves 71 h is held by the grease-holding grooves91 h. When the switch body 3 is turned on, a small amount of the grease11 is discharged from the guide grooves 71 h. However, the grease 11discharged from the guide grooves 71 h is stored in the grease supplyreservoirs 72 a and 92 a, as shown in FIG. 8. Further, at this time, thegrease supply protrusions 71 e and 91 e are inserted into the greasesupply reservoirs 92 a and 72 a, respectively, and the grease 11 storedin the grease supply reservoirs 72 a and 92 a is attached to the greasesupply protrusions 71 e and 91 e.

When the finger is released from the knob 9 to allow the knob 9 to bereturned to its original position by the resilience of the click board31, the grease 11 attached to the grease supply protrusions 71 e and 91e returns to the guide grooves 71 h. This reduces the loss of the grease11 to a very small amount.

Next, a description will be given of an operation feeling produced byoperating the knob 9.

During a time period from the start of pushing of the knob 9 by theoperator to the switch-on of the switch body 3, the rails 91 a slidewithin the guide grooves 71 h. At this time, since the grease 11 havinga high viscosity exists between the rails 91 a and the guide grooves 71h, the rails 91 a are moved slowly, and what is more, generation ofnoise, such as rattling or sliding noise of the knob 9, is suppressed.Thus, the operator feels an appropriate resistance on his fingertip whenpressing the knob 9, and the knob 9 moves quietly and slowly withoutrattling. As a result, the operator can obtain an upscale impression ofthe push type switch. Further, also when the click board 31 is invertedin shape, the grease 11 having a high viscosity softens the clickfeeling, which enhances the upscale impression.

Next, a description will be given of the effects of the presentembodiment.

According to the push type switch, the grease 11 having a viscositywithin the range of 1000 to 2750 Pa is used. Therefore, when theoperator pushes the knob 9, an appropriate pressure acts on a finger ofthe operator, and the knob 9 moves quietly and slowly with littlerattling. As a result, the operator can obtain an upscale impression ofthe push type switch.

Further, since the grease 11 is a fluorine-based grease, no significantchange in the viscosity is caused by temperature, which makes itpossible to prevent the operation feeling from being changed due tochanges in temperature.

Furthermore, since the grease-holding grooves 91 h, the grease supplyreservoirs 72 a and 92 a, and the grease supply protrusions 71 e and 91e are employed, the loss of the grease 11 is small even after the pushtype switch is used for a long time period. This makes it possible tomaintain the upscale impression of the push type switch for a long timeperiod.

It should be noted that although in the present embodiment, thefluorine-based grease is used as the grease 11, this is not limitative,but an olefin-based grease, for example, may be employed as the grease11.

Further, although in the present embodiment, the grease-holding grooves91 h are formed in the rails 91 a, it is not necessarily required toform the grease-holding grooves 91 h in the rails 91 a.

It should be noted that although the grease supply protrusions 71 e andthe grease supply reservoirs 72 a are formed in the casing 7, and thegrease supply protrusions 91 e and the grease supply reservoirs 92 a areformed in the knob 9, it is not necessarily required to provide thegrease supply protrusions 71 e and 91 e, or the grease supply reservoirs72 a and 92 a.

Further, although in the present embodiment, the guide grooves 71 h areformed in the casing 7, and the rails 91 a are provided in the knob 9,this is not limitative, but the guide grooves may be formed in the knob9 and the rails may be provided in the casing 7.

It should be noted that the number of the guide grooves 71 h and that ofthe rails 91 a are not limited to three.

Next, a description will be given of a test performed for defining arange of viscosity of grease producing the upscale impression of thepush type switch during operation thereof.

Table 1 indicates samples and viscosities of greases employed in thetest. TABLE 1 Samples Used in Evaluation Test Viscosity of Grease SampleName (torque: Pa) Sample A 0 (No grease) Sample B 220 Sample C 750Sample D 1230 Sample E 1930 Sample F 2500 Sample G 4000

FIG. 9 is a graph showing the relationship between the average ranks ofsamples and the viscosities of greases; FIG. 10 is a view showing atable of evaluation items and evaluation scores of the samples on aseven-point (−3 to 3-point) scale; FIG. 11 is a graph showing therelationship between the average evaluation scores of the respectivesamples as to the feeling of softness obtained during operation of theknob and the viscosities of the greases; FIG. 12 is a graph showing therelationship between the average evaluation scores of the respectivesamples as to rattling of the knob and the viscosities of the greases;and FIG. 13 is a graph showing the relationship between the averageevaluation scores of the respective samples as to generation of noiseduring the operation of the knob and the viscosities of the greases.

As shown in Table 1, a push type switch which has no grease applied tosliding portions (the guide grooves 71 h and the rails 91 a) is referredto as Sample A. Push type switches which have greases having differentviscosities applied to sliding portions thereof are referred to asSample B to Sample G, respectively. The viscosities of the greases usedin the respective samples are shown in Table 1.

Then, a plurality of monitors were caused to operate Samples A to G, andthe ranks or places of Samples A to G in the respective ranks orders asto the relative merits and demerits thereof concerning the operationfeeling, rattling, and noise were determined on a sample-by-samplebasis, and the averages of the ranks or places of each of Samples A to Gin the rank orders were obtained. The results are shown in FIG. 9.

The monitors felt upscale impressions from samples of a third place orhigher in the average rank order. The viscosities of the greases used inthe samples of the third place or higher are within a range of 1000 Pato 2750 Pa.

Then, Samples A to G were evaluated as to the feeling of softness(feeling of resistance), the rattling of the knob, and the generation ofnoise during the operation of the knob. To express results of evaluationin numerical points, as shown in FIG. 10, evaluations concerning eachitem were classified into seven levels in which positive evaluations areassigned scores of 3, 2, and 1 in decreasing order of the evaluations,whereas negative evaluations are assigned scores of −1, −2, and −3 indecreasing order of the evaluations. Further, when neither of thepositive evaluations and the negative evaluations can be given, anevaluation score of 0 was imparted.

The monitors evaluated Samples A to G as to each item of evaluation. Therelationship between the respective average evaluation scores of SamplesA to G concerning the feeling of softness and the viscosities of thegreases is shown in FIG. 11; the relationship between the respectiveaverage evaluation scores of Samples A to G concerning the rattling ofthe knob and the viscosities of the greases is shown in FIG. 12; and therelationship between the respective average evaluation scores of SamplesA to G concerning noise and the viscosities of the greases is shown inFIG. 13.

As shown in FIG. 11, the average evaluation score concerning the feelingof softness is higher as the viscosity of the grease is higher. However,the feeling of softness and the upscale impression of the push typeswitch during operation thereof do not coincide with each other. Whenthe viscosity is larger than 2500 Pa, the feeling of softness becomesexcessive, and most of the monitors felt extreme reduction in thefeeling of input operation (feeling of pushing in the push type switch).

Referring to FIG. 12 and FIG. 13, however, the average evaluation scoresconcerning the rattling of the knob and the generation of noise arehigher as the viscosity of the grease is higher, and hence the totalevaluation makes it possible to obtain the upscale impression even afterthe viscosity of the grease exceeds 2500 Pa. Therefore, as shown in FIG.9, the range of the viscosity of the grease where the upscale impressioncan be obtained was determined to be 1000 to 2750 Pa.

FIG. 14 is a graph showing the relationship between the sliding speedand the sliding resistance of the knob exhibited when a low-viscositygrease is used or when a high-viscosity grease is used.

Referring to FIG. 14, in the case where the low-viscosity grease is used(Sample B), which is indicated by a dotted line, the sliding resistanceF of the knob 9 does not become so large even when the sliding speed vof the knob 9 becomes higher. On the other hand, in the case where thehigh-viscosity grease is used (Sample D), which is indicated by a solidline, when the sliding speed v of the knob 9 becomes higher, the slidingresistance F of the knob 9 increases at a higher rate than the rate ofincrease in the sliding speed v.

Assuming that the coefficient of viscosity of a grease is represented byC, and the sliding speed of the knob by v, the sliding resistance F ofthe knob 9 can be obtained by the following equation:F=Cv

As described above, if the high-viscosity grease is used, the slidingresistance F of the knob 9 increases at a higher rate than the rate ofthe increase in the sliding speed v, so that a sharp change in load onthe knob 9 is alleviated. This action mainly leads to enhancement of theoperation feeling produced when the click board 31 is inverted in shape.

Based on the results of the test described above, the range of theviscosity of the grease 11 was determined to be 1000 to 2750 Pa.

Since it is difficult to describe the difference between the operationfeeling of Sample C and that of Sample D, the difference is representedby a graph shown in FIG. 15.

In FIG. 15, the horizontal axis represents the stroke of the knob, andthe vertical axis represents the speed of the knob and the load on theknob.

For purposes of ease of comparison between the operation feeling ofSample C and that of Sample D, the pushing force applied to the knob 9during a time period from the start of pushing the knob 9 to theinversion of the click board 31 (between strokes S0 and S1) was set tobe equal between Sample C and Sample D.

A curve VC represents the relationship between the stroke (S) and thespeed (V) of a knob 9 of Sample C, a curve VD represents therelationship between the stroke (S) and the speed (V) of a knob 9 ofSample D, a curve FC represents the relationship between the stroke (S)and load (F) on the knob 9 of Sample C, and a curve FD represents therelationship between the stroke (S) and load (F) on the knob 9 of SampleD.

As shown in FIG. 15, between the strokes S0 and S1, the knob 9 of SampleD moves a little more slowly than the knob 9 of Sample C.

During a time period from the inversion of the click board 31 to thestop of the knob 9 (between strokes S1 and S2), both the speed (V) andthe load (F) sharply change in Sample C, whereas in Sample D, both thespeed (V) and the load (F) change more slowly than in Sample C. Thismeans that in Sample C, the click feeling is sharpened, whereas inSample D, the click feeling is softened.

As described above, the slower motion and the softer click feeling ofthe knob 9 give the upscale operation feeling thereto.

Next, a description will be given of variations of the first embodiment.

FIG. 16 is a cross-sectional view showing a sliding portion of a firstvariation of the first embodiment.

As shown in FIG. 16, in the first variation, each grease supplyprotrusion 91 e has a side surface formed with a plurality of grooves 91q.

In the first variation, the grease 11 becomes easier to be attached tothe grease supply protrusions 91 e due to the grooves 91 q. As a result,it is possible to enhance the circulation of the grease 11.

FIG. 17 is a cross-sectional view showing a sliding portion of a secondvariation of the first embodiment.

As shown in FIG. 17, in the second variation, a portion of each rail 91a accommodated in the associated grease supply reservoir 92 a is formedwith inflated portions 91 r. The inflated portions 91 r are configuredto have a shape to be fitted in the grease supply reservoir 71 k. Whenthe grease supply protrusions 71 e are inserted into the grease supplyreservoirs 92 a, the inflated portions 91 r return the grease 11 withinthe grease supply reservoirs 71 k to the guide grooves 71 h.

In the second variation, since the grease 11 within the grease supplyreservoirs 71 k can be returned to the guide grooves 71 h by theinflated portions 91 r, it is possible to enhance the circulation of thegrease 11, similarly to the first variation.

FIG. 18 is an enlarged cross-sectional view showing part A of a thirdvariation of the first embodiment.

As shown in FIG. 18, in the third variation, grease-holding grooves 71 rare formed in respective opposed inner surfaces of each guide groove 71h. The grease-holding grooves 71 r extend in parallel with the guidegroove 71 h.

In the third variation, since the grease-holding grooves 71 r are formedin addition to the grease-holding grooves 91 h, it is possible tofurther reduce the loss of the grease 11.

FIG. 19 is an enlarged cross-sectional view showing part A of a fourthvariation of the first embodiment.

As shown in FIG. 19, in the fourth variation, grease-holding grooves 71r are formed in respective opposed inner surfaces of each guide groove71 h, and the grease-holding groove 91 h is eliminated from the topsurface of each rail 91 a (surface opposed to the bottom surface of eachguide groove 71 h).

The fourth variation provides the same advantageous effects as providedby the first embodiment shown in FIG. 1.

FIG. 20 is an enlarged cross-sectional view showing part A of a fifthvariation of the first embodiment.

As shown in FIG. 20, in the fifth variation, grease-holding grooves 91 sare formed in respective opposite side surfaces of each rail 91 a, andthe grease-holding groove 91 h is eliminated from the rail 91 a.

The fifth variation provides the same advantageous effects as providedby the first embodiment shown in FIG. 1.

FIG. 21 is an enlarged cross-sectional view showing part A of a sixthvariation of the first embodiment.

As shown in FIG. 21, in the sixth variation, a key 91 t is formedinstead of forming the grease-holding groove 91 h in the top surface ofeach rail 91 a (surface opposed to the bottom surface of each guidegroove 71 h). The key 91 t creates a gap G for holding the grease 11between the top surface of the rail 91 a and the guide groove 71 h.

The sixth variation provides the same advantageous effects as providedby the first embodiment shown in FIG. 1.

FIG. 22 is a cross-sectional view showing a sliding portion of a seventhvariation of the first embodiment.

As shown in FIG. 22, in the seventh variation, a plurality ofgrease-holding grooves 91 u are formed in the opposite side surfaces ofeach rail 91 a, instead of forming the grease-holding groove 91 h in thetop surface of the rail 91 a. The grease-holding grooves 91 u extend ina direction orthogonal to the direction of the length of the rail 91 a.

The seventh variation provides the same advantageous effects as providedby the first embodiment shown in FIG. 1.

FIG. 23 is an exploded perspective view of a push type switch accordingto a second embodiment of the present invention; FIG. 24 is aperspective view of the FIG. 23 push type switch, in a state having partof a casing thereof cut off, and presented in an inverted position; FIG.25 is an enlarged view of part B appearing in FIG. 24; and FIG. 26 is across-sectional view of the FIG. 23 push type switch.

Component parts identical to those of the first embodiment aredesignated by identical reference numerals, and detailed descriptionthereof is omitted, while only component parts different inconfiguration from the first embodiment will be described hereinafter.

As shown in FIGS. 23 to 26, the push type switch is comprised of aswitch body 3, a printed wiring board 5, a casing 207, a knob 209, and aslider 210.

As distinct from the first embodiment in which the movable member isformed by the knob 9 alone, in the second embodiment, a movable memberis formed by the knob 209 and the slider 210.

The casing 207 includes a hollow section 271, a lid 272, and pillar-likeportions 273. The casing 207 contains the slider 210, and is rigidlyfixed to the printed wiring board 5. The hollow section 271 has a hollowprismatic shape. The lid 272 is connected to one end of the hollowsection 271. The lid 272 is formed with a hole 272 a, and an innersurface of the lid 272 is formed with three grease supply reservoirs(second grease reservoirs) 272 b (see FIG. 25). The hollow section 271has three pillar-like portions 273 arranged therein. The pillar-likeportions 273 are connected to the hollow section 271 and the lid 272.The pillar-like portions 273 are each formed with a guide groove 273 a.The guide grooves 273 a communicates with the respective associatedgrease supply reservoirs 272 b. Part of one end of each pillar-likeportion 273 is cut out to thereby form a grease supply protrusion 273 b.

The knob 209 includes a skirt 291 and a pushed portion 292. The skirt291 has a hollow prismatic shape, and is formed with two holes 291 p.The pushed portion 292 is in the form of a flat plate, and connected toone end of the skirt 291. The periphery of the pushed portion 292protrudes from a side surface of the skirt 291.

The slider 210 includes a first hollow portion 211 and a second hollowportion 212.

The first hollow portion 211 has a hollow prismatic shape, and rails 211a are respectively formed at three portions of the sides of the firsthollow portion 211. One end of each rail 211 a protrudes from one endface of the first hollow portion 211, and the protruding portion servesas a grease supply protrusion 211 b (see FIG. 26). The rails 211 a areslidably inserted into the respective associated guide grooves 273 a ofthe casing 207. This enables the slider 210 to slide on the casing 207.When the slider 210 is lifted by a click board 31, the grease supplyprotrusions 211 b are inserted into the respective associated greasesupply reservoirs 272 b of the lid 272.

The first hollow portion 211 has one end thereof formed with threeoverhang portions 211 c adjacent to the rails 211 a. The overhangportions 211 c are each formed with a grease supply reservoir 211 d. Thegrease supply reservoirs 211 d receive one ends of the rails 211 a.Further, when the slider 210 is lifted by the click board 31, the greasesupply reservoirs 211 d receive the grease supply protrusions 273 b ofthe pillar-like portions 273, respectively.

The first hollow portion 211 has an inner side wall provided with apushing piece 211 e for pushing the switch body 3, and a reinforcingplate 211 f supporting the pushing piece 211 e (see FIG. 26).

The second hollow portion 212 has a hollow prismatic shape. It is nextsmaller in size than the first hollow portion 211, and connected to theother end of the first hollow portion 211. The second hollow portion 212protrudes from the casing 207 via the hole 272 a. The second hollowportion 212 has side surfaces formed with two protrusions 212 a. Theprotrusions 212 a are inserted into the associated holes 291 p of theknob 209. This fixes the knob 209 to the second hollow portion 212

The second embodiment provides the same advantageous effects as providedby the first embodiment.

It is further understood by those skilled in the art that the foregoingare the preferred embodiments of the present invention, and that variouschanges and modification may be made thereto without departing from thespirit and scope thereof.

1. A push type switch comprising: a switch body; a fixing member towhich said switch body is rigidly fixed; a movable member slidablysupported by said fixing member such that said movable member cantransmit a pushing force to said switch body; and a grease applied tosliding portions of said fixing member and said movable member, whereina viscosity of said grease is within a range of 1000 to 2750 Pa.
 2. Apush type switch as claimed in claim 1, wherein said grease is afluorine-based grease.
 3. A push type switch as claimed in claim 1,wherein a guide groove is formed in one of said fixing member and saidmovable member, and a rail for sliding relative to said guide groove isformed on the other of said fixing member and said movable member.
 4. Apush type switch as claimed in claim 2, wherein a guide groove is formedin one of said fixing member and said movable member, and a rail forsliding relative to said guide groove is formed on the other of saidfixing member and said movable member.
 5. A push type switch as claimedin claim 3, wherein a first grease reservoir is formed in at least oneof said guide groove and said rail.
 6. A push type switch as claimed inclaim 4, wherein a first grease reservoir is formed in at least one ofsaid guide groove and said rail.
 7. A push type switch as claimed inclaim 3, wherein a second grease reservoir is formed in one end ofeither said guide groove or said rail.
 8. A push type switch as claimedin claim 4, wherein a second grease reservoir is formed in one end ofeither said guide groove or said rail.
 9. A push type switch as claimedin claim 5, wherein a second grease reservoir is formed in one end ofeither said guide groove or said rail.
 10. A push type switch as claimedin claim 6, wherein a second grease reservoir is formed in one end ofeither said guide groove or said rail.